Plate electrode

ABSTRACT

A one-piece disposable electrode having a flat flexible base of non-electrical conductive sheet material. An electrical conductive skin is secured to one side of the base. The skin is divided into separate sections engageable with distinct portions of a body. Clamps and cables are used to attach the electrode to an electrical-surgical machine, an electrocardiograph recording mechanism, or a device coupled to a cardiac catheter.

United States Patent 1191 Bolduc PLATE ELECTRODE Lee R. Bolduc,Minneapolis, Minn.

Assignee: Medical Plastics Inc., Minneapolis,

' Minn.

Filed: Nov. 25, 1970 Appl. No.: 92,767

Related 0.5. Application Data Continuation-in-part of Ser. Nos. 711,949,March 1 1, 1968, Pat. No. 3,543,760, and Ser. No. 866,630, Oct. 7 15,1069, Pat. No. 3,642,008.

inventor:

US. Cl. ..128/2.06 E, 128/416 Int. Cl. ..A6lb 5/04 Field of Search..128/303.13303.l9, 128/404, 410, 413, 416-418, 2.06 E, 422; 24/243,243.15; 339/228, 229, 230,261,

[5 6] References Cited UNITED STATES PATENTS Frankel ..339/97 Frankel....339/3l Buck ..24/252 Eads ..339/176 1March 13, 1973 PrimaryExaminer-Lawrence W. Trapp AttorneyBurd, Braddock & Bartz [57] ABSTRACTA one-piece disposable electrode having a flat flexible base ofnon-electrical conductive sheet material. An electrical conductive skinis secured to one side of the base. The skin is divided into separatesections engageable with distinct portions of :a body. Clamps and cablesare used to attach the electrode to an electrical-surgical machine, anelectrocardiograph recording mechanism, or a device coupled to a cardiaccatheter.

37 Claims, 16 Drawing; Figures 20/ 204 I j 202 ll l CONVENTIONAL 1]208/1 E K e RECORDING MECHANISM ll 206 l llll I b l l") I IllPATENTEDHARHIGTS 720,209

SHEET 30F 4 20 207 Z00 v I II I I I I E .I p CONVENTIONAL 208 E K e IREcoRDI e 209A I .---207, MECHANISM I |l F J0 MW? ME I I 2/2 209 3K 21 kI I I 1 HI Y I wJE ILE CONVENTIONAL 1 E Ks I RECORDING MECHANISM I 226Q7 I Ill I III I j 244 241 242 23$ Z1 u. gig I CONVENTIONAL a l II v EKGZ46 RECORDING 1 "fl7" MECHANISM \252 25% 25 3 Iii 9 239 i j 74 INVENTOR.FILE-L25 LEE R. BOLDUC BY .fimcfi/laaldoczfiwf AT TORNEYS I PLATEELECTRODE CROSS REFERENCE TO RELATED APPLICATIONS This application is acontinuation-in-part of U. S. Patent application Ser. No. 711,949, filedMar. 11, 1968, now U. S. Pat. No. 3,543,760 and U. S. Pat. applicationSer. No. 866,630, filed Oct. 15, 1969, now U. S. Pat. No. 3,642,008.

BACKGROUND OF THE INVENTION In 1907, Pozzi demonstrated fulguration as acure for malignant disease to the Paris Academy of Medicine, using anOudin resonator and unipolar current of a frequency around half amillion cycles per second. His results were by no means uniform, and itwas left to Iredell and Turner, in 1919, to demonstrate true diathermyby providing a plate, 6 by 12 inches, for the return circuit. Theyshowed that the effects of the treatment were entirely due to heatdestruction of tissues and were first to use a water pipe to ground boththe indifferent electrode and the patient. This contribution to safetyhas remained until the present day. In use, heat is developed at boththe active electrode and the indifferent or ground electrode, commonly alead plate, in surface contact with the skin of a patient. The heatgenerated is inversely proportional to the square area of theseelectrodes. The ground electrode must be of a certain size and has tomake uniform contact all over its surface so that the heat is diffusedover a wide area. If the ground electrode has point contacts, thepatient can be severely burned. In some instances, two ground electrodesare used at the same time to insure adequate grounding of the patient.

Efficient functioning and safety of electrical-surgical machines dependsupon an unimpaired return of current via the indifferent groundelectrode and its cable. If this fails, then the current will choose thenext best route, which will mean a short circuit to ground with aconsequent risk of a diathermy burn. Some machines are equipped with aground test stud that requires the operating staff, before eachoperation, to check the circuit. This system only monitors thecontinuity of the cable and its attachment to the ground electrode. Itdoes not monitor the electrical contact and conductivity between theground electrode and the patient.

Various materials are used for the ground plate electrodes. The materialshould be a good conductor and easily malleable. Lead plates havebeenthe most practical to use. Electrodes have been made of stainless steel,aluminum, brass, silver, zinc and tin, as suggested by Wappler, U. S.Pat. No. 1,662,446; Huth, U. S. Pat. No. 1,853,814; Ruben, U. S. Pat.No. 1,973,911; and Howell, U. S. Pat. No. 2,943,628.

Electrodes including plate electrodes are used in conjunction withconventional recording mechanisms used to monitor the electrical signalfrom a patients heart. It is a common practice to engage separateelectrodes at different points relative to the front of the patientsbody to make a separate contact with the body. An electrode assembly isdesigned for this use and is disclosed in U. S. Pat. Nos. 2,943,628 and3,476,104.

The use of catheters in the human provides potential for electrocutionbecause the instruments can be conductors of electricity. Many of theelectrocution accidents are caused by faulty equipment and people whofail to recognize the hazards. The remedy to this problem is to groundall elements of the system. Many factors make total grounding of allelements of the system at all times almost impossible. The plateelectrode of the invention can be used with catheters and otherelectrical apparatus to reduce these electrocution hazards.

SUMMARY OF THE INVENTION The invention relates to an electrode usable toground a patient or monitor electrical signals generated by the patient.The electrodes are used in conjunction with electrosurgical units, as acomponent of an electrocardiograph apparatus, and with a cardiaccatheter. The electrode has a flexible electrically insulated basecarrying an electrically conductive skin means. The entire skin means issecured to one side of the base.

One form of the electrode has a flexible base sheet member carryingelectrically conductive skin means separated into two skin sections. Aclamp having a pair of spaced electrical contact members with flatsurfaces is attached in surface engagement with the separate skinsections of the ground plate electrode. Another form of the electrodehas a plurality of spaced electrically conductive skin means carried bya flexible sheet base member. The separate electrical conductive skinmeans are connected with suitable connectors as wires, clamps and jacksto an electrocardiograph recording mechanism.

IN THE DRAWINGS FIG. 1 is a diagrammatic view of the electro-surgicalunit equipped with a ground plate electrode of the invention;

FIG. 2 is a perspective top view of the electrode positioned on anoperating table;

FIG. 3 is an enlarged sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is a sectional view similar to FIG. 3 showing the flange foldedover adjacent the base of the electrode;

FIG. 5 is an enlarged plan view of the ground plate electrode showingthe area indicia lines and the fold line for the end flange;

FIG. 6 is a diagrammatic view of an electro-surgical unit having a splitskin ground plate electrode attached to a bipolar clamp connected tocircuit testing unit;

FIG. 7 is an enlarged sectional view taken along the line 77 of FIG. 6;1

FIG. 8 is an enlarged sectional view taken along lin Z 88 of FIG. 6;

FIG. 9 is a plan view of a split ground plate electrode having a clamplocater hole with parts broken away;

FIG. 10 is a diagrammatic view of an electrode connected to anelectrocardiograph recording mechanism;

FIG. 11 is a modified electrode connected to an electrocardiographrecording mechanism;

FIG. 12 is an enlarged sectional. view taken along the line l212 of FIG.10;

FIG. 13 is a further modification of a plate electrode connected to anelectrocardiograph recording mechanism;

FIG. 14 is a sectional view of an electrode having a plastic foam base;

FIG. is a diagrammatic view of a device having a cardiac catheterattached to a plate electrode located under the body of a patientpositioned on a table; and

FIG. 16 is a diagrammatic view, partly sectioned, of the cardiaccatheter and plate electrode of FIG. 15.

Referring to the drawings, there is shown in FIG. 1, an electro-surgicalunit indicated generally at 10 illustrated in an operating environmenttheater on a patient 11 lying on a table 12. An upright base 13 supportsthe table 12 above floor 14 to locate patient 11 in a convenientposition for surgeon 16.

The electro-surgical unit 10 uses high frequency current from a portabletransformer 17 connected to a power supply and an active electrode 18 bya cable or line 19. A ground plate electrode or indifferent electrode,indicated generally at 21, connected by a cable or line 22 totransformer 17 completes the circuit through the patient. A releasableconnector or clamp, indicated generally at 23, electrically couplescable 22 with the ground plate electrode 21. The opposite end of cable22 is connected to a test and control unit, indicated generally at 24,plugged into the transformer 17. A test and control unit is disclosed inU. S. Patent application Ser. No. 866,630, now U. S. Pat. No. 3,642,008.Under operating conditions, high frequency currents flow through thepatient 11 from the active electrode 18 and return to the ground throughelectrode 21 located under the patient 11 on the table 12. The placementof the ground plate electrode 21 on the patient varies according 'to thesurgical area. The electrode 21 may be placed under the buttock, orwrapped around an arm or leg, to provide a maximum area of flesh or skincontact. For proper patient grounding it has been found that asubstantial electrical surface contact is required between patient 11and electrode 21. An example of electrode 21 is shown in FIG. 5. Thiselectrode has 154 square inches of electrically conductive skin. Therequirement is that there be substantial electrical surface contact witha body for proper grounding. If the area is too small, chances forburning are substantially increased. A 100 square inch contact areaprovides for a margin of safety. The ground plate electrode 21 isoperative with skin areas of less than 100 square inches, as well aswith skin areas that are greater than 100 square inches. Plateelectrodes usable with children, may have only 50 square inches ofelectrically conductive skin. The effectiveness of the ground plateelectrode is also dependent upon the conductivity of the skin of'thepatient, as well as the type of metal used in the ground plateelectrode.

Ground plate electrode 21 is a generally rectangular flexible sheetmember capable of being shaped to fit the contour of the parts of thebody, as a leg or arm. As shown in FIG. 2, the electrode 21 is placed onthe top of table 12 so as to engage a large area of the skin in theposterior of the patient 11.

As shown in FIG. 3, ground electrode 21 has a flat and flexible baselayer 26 which may be made of cardboard, paper or similar flexible andelectrically insulative material. Located over the top surface of thebase layer 26 is an electrical conductive skin 27. Skin 27 can be ametal sheet or foil, as aluminum foil. The base layer 26 is impregnatedwith a plastic material which bonds the skin 27 to the base layer 26.The plastic material increases the thermal characteristics of theelectrode so that it can be placed in the autoclave for sterilizationand is liquid proof.

A specific example of electrode 21 usable as a disposable item with anelectro-surgical unit is as follows: The base layer is an 11 X 14 inchrectangular sheet of flexible, electrically insulative, cardboard about0.024 0.022 inch thick. A 0.003 inch aluminum foil covers the entire topsurface of the cardboard and is bonded to the top surface of thecardboard with plastic bonding material impregnated in the cardboard.The plastic material makes the cardboard liquid and waterproof andautoclavable.

An end flange or flap 28 of electrode 21 is turned over and secured tothe back of the base 26 with a bonding material 29, as adhesive or glue,to form a stop edge 31. The releasable connector 23 cooperates with stopedge 31 to prevent the accidental removal of the connector. The plasticimpregnated in the base 26 may be utilized to bond the base and flange28 together thereby to eliminate the bonding material 29.

As shown in FIG. 4, flange 28 can be folded under the base to providethe stop edge 31 without securing the flange to the base.

As shown in FIG. 5, ground electrode 21 has a generally rectangularshape with the flange 28 extended transversely across the electrode 21.The skin 27 of the electrode has broken guide lines 32 to outline asquare area approximately square inches. The lines are parallel to thesides and ends of the electrode. Lines 32 outline a 10 inch square. In asimilar manner broken lines 33 outline a rectangular area which isgenerally 100 square inches. Lines 33 also extend parallel to the sidesand ends of the electrode and outline an area of approximately 100square inches. Extended across the end of electrode 27 is a broken foldline 34 providing a guide for turning flange 31 under base layer 26 asshown in FIG. 8. Flange 28 may be prefolded and secured to base layer 26as shown in FIG. 3.

Referring to FIG. 6, there is shown a diagrammatic view of anelectrical-surgical unit, indicated generally at 106, connected to asplit ground plate electrode 107 with a cable 108 and a releasablebipolar connector or clamp, indicated generally at 109. The cable 108connects the clamp to a circuit testing unit 111 plugged into theelectrical-surgical unit 106. The electric circuit through the patientis completed by the use of an active electrode coupled to a cableextended back to the electrical-surgical unit 106, as illustrated inFIG. 1.

The ground plate electrode 107 is a rectangularshaped one-piece sheetmember having a transverse flap or scored end 112 cooperating with theclamp 109 to prevent the accidental disengagement of the clamp from theground plate electrode. The corners 1l3 and 114 are curved or arcuate toeliminate sharp points and edges which may cut the patient or personnelin the operating theater.

Asshown in FIG. 7, the ground plate electrode 107 has a flat andflexible base 114 which may be made of cardboard, paper, or similarflexible and electrically insulative material. Secured to the top of thebase 114 is a pair of spaced electrically conductive skins 116 and 117having flat and smooth surfaces. The skins 116 and 117 are located in a'side-by-side relation and are separated from each other by alongitudinal space 118 extended down the longitudinal center line of the174 permits the easy and convenient folding of the flap prior toinsertion into the clamp. The corners 176 and 177 of the opposite end ofthe electrode are rounded or curved to eliminate any sharp points oredges. Inwardly of the flap 173 in the midsection of the base 168 is aclamp locater hole 178. The electrode 167 can be provided with two otherholes 178A and 178B for the purpose of locating and holding a clamp onthe electrode.

Referring to FIG. 10, there is shown a bipolar electrode, indicatedgenerally at 200, used in conjunction with a conventionalelectrocardiograph (EKG or ECG) recording mechanism 201 or an ECGviewer. Lines or cables 202 and 203 connected to clamps 204 and 206foam, polystyrene foam and polyester foam. Located along the oppositesides of the top of base 207 are elongated longitudinal conductive skins208 and 209. The skins 208 and 209 along one edge of the base have por'tions 208A and 209A that extend toward each other so that they can beengaged with a single bipolar clamp, as shown in FIGS. 6 and 8. Eachskin can be a relatively thin layer of metal, as metal foil or sprayedmetal including but not limited to aluminum, tin, copper, silver, andanodized aluminum. The electrically conductive skins 208 and 209 can besprayed or deposited on the base 207. The skins can be silver dust,carbon particles or like electrical conductive particles, comprising afiller for polyethylene, polyurethane or polypropylene plastic material.The filler is preferably approximately 80 per cent of the plasticmaterial.

FIG. 14 shows an electrode 210 having a plastic foam base 211 carryingan electrical conductive skin or coating 212. Base 211 can bepolyurethane foam bonded to an aluminum foil skin 212.

Referring to FIG. 1 1, there is shown a further modification of theelectrode, indicated generally at 213, connected to a conventionalelectrocardiograph recording mechanism 214 with cables 227 or lines 216,217 and 218 and clamps 219, 221 and 222. Electrode 213 has a relativelyflat flexible base 223 of electrically non-conductive sheet material.The base may be made of the same material as the base 204 describedabove. Secured to the corner portions of the base 223 are a plurality ofseparated electrically conductive skins 224, 225, 226 and 227. The skins224-227 are substantially equal in area and shape and may be ofelectrical conductive metal or coating that is the same as skins 208 and209 described above. For example, each skin has a dimension of 2-%inches by 4 inches. The base has a size of 8 inches by 14 inches. Theskin 227 can be alternatively connected to the recording mechanism 214in lieu of one of the other skins 224, 225 and 226, depending on theposition of the electrode relative to the patient.

Referring to FIG. 12, there is shown a clamp 222 in assembled relationwith the electrode 213. The clamp 222 has a U-shaped body havingrelatively flat upper and lower arms 228 and 229 separated from eachother with a transverse slot 231. The outer ends 228A and 229A of thearms 228 and 229 are directed inwardly toward each other to grip theopposite sides of the electrode 213. Line 218 is attached to the base ofthe arms. Arms 228 and 229 are biased toward each other with a pivotallymounted lever 231 attached to a transverse lip 232. The lip 232 can havea plurality of teeth to grip the base. Opposite ends of the lip 232 havehave short projections rotatably mounted in holes in upright ears 233secured to opposite sides of the top lever 228. The outer end 234 of thelever 231 has a step or projection to provide a grip to permit the leverto be moved as indicated by the arrow 236. As shown in FIG. 11, the lip232 is in the over-center position forcing the lever 23] against the arm229 and thereby biases the arms 228 and 229 together into engagementwith opposite sides of the electrode 213. When lever 23] is moved awayfrom arm 229, lip 232 will also move away from arm 229 thereby openingthe clamp. The clamps shown in FIGS. 10,11 and 13 can be the same asclamp 222.

Referring to FIG. 13 there is shown a further modification of theelectrode, indicated generally at 237, connected to conventionalelectrocardiograph recording mechanism 238 with cables or lines 239,240, 241 and clamps 242, 243 and 244. The electrode 237 has a generallyflat base 246 of non-conductive sheet material similar to the base 207.Secured to one side of the base are a pair of first skins 247 and 248located on opposite corners of the base 246. A second skin 249 isattached along the entire opposite side of the base. A lead orelectrically conductive strip 251 extends from the skin 248 to one edgeof the base and ends in an end tab 252.

A cover or mast 253 of non-electrically conductive material is securedto the base to cover the strip 251. The base and skins of electrodes 223and 237 can be the same materials as that described for the electrode200. The electrodes can vary in size and shape. For ex ample, theelectrodes could be round, square, triangular, as well as rectangular inshape. The skins can also vary in size and shape. The base can be thesize ofa bed sheet. The skins can be located in; the mid-portion of abed sheet-sized base. The process of applying or attaching the skins tothe base may include an adhesive bond, a bonding reaction between thebase and skins, as well as plastic impregnated material in the base toattach the skins to the base.

In use, the electrode is placed under the body of a patient located in aprone position. The electrical conductive skins are in electricalengagement with the back of the patient. With the electrode coupled tothe electrocardiograph recording mechanism, an electrocardiogram can beprepared in a conventional manner.

The body of the patient is a shield against outside electricalinterference and the weight of the body serves to provide effectiveelectrical contact with the skins of the electrode.

The electrode of the invention is a one-piece disposable member havingone or more electrically conductive skin means for providing anelectrical contact between a patient and the electrode. The electrode isusable as a ground plate electrode in electro-surgical procedures aswell as EKG electrodes to monitor electrocardiographic impulses.

ground plate electrode 107. The skins 116 and 117 may be sheet metal ormetal foil, as aluminum foil, bonded to the base 114. The skins havesmooth continuous top surfaces and outer peripheral edges 119 that areturned down into the adjacent edges of the base 114. The turned downedges 119 provide rounded edges around the entire ground plate, therebyeliminating any sharp edges which may injure the patient or operatingpersonnel. The base 114 is impregnated with a plastic material whichbonds the skins 116 and 117 to the top of the base. Other chemicals andmaterials can be used to treat and liquid-proof the base. The plasticmaterial increases the thermal characteristics of the ground plateelectrode 107 so that it can be placed in an autoclave forsterilization. In addition, the plastic material makes the entire groundplate electrode liquid-proof. The plastic material functions to maintaina continuous bond between the skins and the base so that the elec trodemay be flexed and wrapped around a patient without separating the skinfrom the base or cracking the base. The back side of the base can beprinted with instruction and inventory code information with ink thatdoes not run or react with liquids or change with heat.

A specific example of the bipolar ground plate electrode 107, usable asa disposable electrode with an electrical-surgical unit, is as follows:The base 114 is a cardboard sheet member having rectangular dimensionsof 8 by 13 inches. The base is electrically insulative cardboard about0.024 0.022 inch thick. The skins 116 and 117 are 0.003 inch aluminumfoil bonded with plastic material to the top of the base. The base 114is entirely impregnated with plastic material. The longitudinal centerspace 118 extends the entire length of the electrode, including the flap112. The space has a width of to 75 inch. The rounded corners have aradius of 1 inch and the flap has a width of 1: inch. Other sizes andshapes of the ground plate electrode and the skins 116 and 117 areintended to be within the scope of the invention.

As shown in FIG. 8, the bipolar clamp 109 has a pair of movable levers122 and 123. Forward portions of thelevers engage opposite sides of theelectrode 107. Lever 122 has a first flat contact nose or plate 122A anda second contact nose or plate 122B separated from the first contactplate with an electrically insulative strip 124. The strip 124 separatesthe lever 122 into separate electrical conductors. The lower lever 123is also separated into two electrical conductors, each having rearwardlydirected plates 123A and 1238 separated from each other with anelectrically insulative strip 125. The plates 123A and 123B have flatupper surfaces that face the flat contact surfaces of the plates 122Aand 1228.

Projected downwardly from the forward portion of the insulation strip124 is a projection or pin 126 which extends through a hole 127 in theground plate electrode 107 and a hole 128 in the insulation strip 125 oflever 123. The hole 127 is located in the space 118 of the ground plateelectrode 107 adjacent the flap 112. Plates 122A and 1228 caneach beprovided with a projection or pin adapted to extend through suitablespaced holes in the ground plate electrode. The use of two pins preventsrotation of the clamp relative to the ground plate electrode. The entireclamp 109, except for the contact plates 122A and 1228 and correspondingsurfaces on the legs 123A and 1238, is coated with an electricallyinsulative material, as an electrically insulative plastic. This coatingprevents the grounding of the patient through the clamp and therebyavoids any contact burns.

The clamp 109 is releasably attached to the ground plate electrode 107by compressing the outer ends of the levers 122 and 123 to open themouth of the clamp by separating the contact plates 122A and 1238 fromthe legs 123A and 1238. The ground plate electrode 107 with the flap 112in the folded position, as shown in FIG. 10, is inserted into the clamp.The middle of the clamp 109 is aligned with the space 118 by aligningthe projection 126 with the hole 127 and the ground plate electrode 107.This positions the contact plate 122A in flat surface engagement withthe skin 116 and the contact plate 1228 in surface engagement with theskin 117. The projection 126, by extending through the hole 128 in thelower lever 123, prevents the accidental removal upon disengagement ofthe clamp 109 from the electrode 107. The only way the clamp 109 can beremoved from the electrode 107 is to depress and open the clamp toremove the projection 126 from the electrode 107. The purpose ofaligning the bipolar clamp 109 so that one electrical contact portion122A engages one skin 116 and the other contact plate 122B engages skin117, is to provide a structure and electrical circuit capable ofmonitoring the efficiency of the electrical conductivity between theground plate electrode 107 and the skin of a patient, as well as theelectrical connection between the clamp 109 and the ground plateelectrode 107 and the continuity of the cable 108. The circuit testingunit 111 functions to form these tests. This unit is disclosed in detailin U. 8. Patent application Ser. No. 866,630, now U. S. Pat. No.3,642,008.

Referring to FIG. 9, there is shown a ground plate electrode 167 havinga generally rectangular shape. Electrode 167 has a flexible base 168which can be made of cardboard, paper, wood, and similar material. Thebase is substantially flat, flexible, and electrically insulative.Attached to the top of the base 168 is a pair of substantially identicalelectrical conductive skins 169 and 171. The skins are spaced from eachother .along the longitudinal center line of the base with a uniformlongitudinal space 172. The skins 169 and 171 are electricallyconductive sheet members having flat continuous and smooth top surfaces.The skins 169 and 171 may be made of sheet metal, metal foil, and likeelectrically conductive material, as aluminum foil. The skins can bebonded or secured to the top of the base 168 with an adhesive or plasticmaterial embedded in the base 168. Other chemicals, bonding and adhesivematerials can be used to treat and liquid-proof the base, as well asbond the skins 169 and 171 to the base 168. The treatment of the baseincreases its thermal characteristics, as well as its resistance tochemical action and liquids, as water, blood, and the like. Theperipheral edges of the ground plate are rounded to eliminate any sharpedges which may injure a patient or operating personnel, as shown inFIG. 7.

One end of the ground plate electrode has a flap or flange 173 extendedacross the end of the electrode and defined with a crease or fold line174. The crease The disposable ground plate electrode shown in FIG. isusable with a patient during surgery, catherization and routineelectro-cardiography to ground and provide an alternate electricalcircuit to the patient. The ground plate is used to minimize theinduction of ventricular fibrillation or multiple extra systoles when anelectrical apparatus is connected to the patient. It is known thatalternating current having 60 cycle per second frequency as used in theUnited States is among the most prone to cause ventricular fibrillation.The threshold of ventricular fibrillation with 60 cycle alternatingcurrent shocks administered to human hearts is very low, in theneighborhood of I80 microamperes. With a safety factor of 10 it has beenfound that shocks exceeding 2 microamperes of 60 cycle alternatingcurrent is regarded as hazardous if delivered directly to the humanheart. Human studies indicate that 60 cycle shocks are 500 to 5000 timesmore dangerous when delivered directly to the heart rather than to thebody surface. The very small magnitude of the shocks capable ofproducing ventricular fibrillation may be appreciated in the light ofthe observation at 60 cycles that currents less than 1 microamperecannotbe detected through the skin. Saline of blood filled cardiac cathetersand pacemaker electrodes are the usual means of gaining electricalaccess to the human heart.

To minimize the electrocution hazards, the voltage 0 difference betweenthe table and the patient and the apparatus or device which may beattached directly to the heart or any other part of the body must beeliminated or reduced to less than a few microamperes of current. In thepresent invention, the apparatus is connected to a disposable groundplate in surface contact with the skin of the patient to shunt or bypassany electrical current that may flow between the apparatus and thepatients heart.

Referring to FIG. 15, there is shown a patient 300 located on a table301. An electrical apparatus, indicated generally at 302, having anelectrically conductive saline solution 303 is connected directly to apatients heart 304 and a source of alternating current 305 used tooperate the apparatus. The apparatus 302 comprises an intra-cardiaccatheter 306. The catheter 306 is an elongated flexible plastic tube forcarrying the saline solution 303 to one of the chambers of the heart304. A coupling 307 is used to connect the catheter to a dye injector31 1. The coupling 307 has an electrically conductive body 308 of metalor the like carrying a non-electrically conductive coating or skin 309.The dye injector 311 may be replaced with a densimeter or otherapparatus for monitoring the condition of the heart.

As shown in FIG. 15, a plate electrode, indicated generally at 312, islocated on the table 301 in surface engagement with the back of thepatient 300. The electrode 312, shown in FIG. 16, has a substantiallyflat base 313 of electrically non-conductive material, as cardboard.Secured to one side of the base 313 is an electrically conductive skin314 of aluminum, tin, or similar conductive metal. The skin and base maybe of the same materials as used in electrodes 21 and 200, describedabove. An electrical conductor 316, as a line or wire, is connected to aclamp 317. Clamp 317 is in engagement with skin 314. The line 316 issecured to the body 308 of the connector 307 and thereby electricallyconnects the fluid or saline liquid 303 with the electrode 312.

In use, the electrode 312 shunts or shorts away most of the current fromthe heart 304. The line 316 and electrode 312 together have lessresistance to the cur-' rent than the saline liquid in the catheter 306.The ratio of the resistance between the line 316 and electrode 312together compared to saline column in the catheter 306 is between 300 to500 to 1. This ratio depends upon the diameter and/or length of thesaline column. Accordingly, the amount of current applied to the heartis reduced by this factor. The plate electrode 312 along with theconnecting line 316 in electrical contact with the saline liquid 303will substantially reduce the incidence of ventricular fibrillation ofthe heart 304.

While there has been shown and described a disposable plate electrodefor use with an electrosurgical unit, an electrocardiograph apparatus,and an intra-cardiac catheter, it is intended that the electrode can beused with other electrical apparatus for either grounding or monitoringelectrical signals from a patient.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. An electrode for engaging the surface of a body and releasablyattachable to an electrical connector having electrical conductor meanscomprising: a onepiece flexible electrically non-conductive sheet memberhaving a generally flat base .layer of flexible material, said baselayer having a surface on at least one side thereof, electricallyconductive flexible skin means substantially covering at least onesurface of the base layer, said skin means having a substantialelectrically conductive external surface area for engagement with thesurface of a body to make a large surface electrical contact between theskin means and the body,

and means securing the entire inner side of said skin means to said onesurface of the base layer, one edge of said sheet member having a flangeterminating in an edge.

2. The electrode of claim 1 wherein: said flangeis secured to the baselayer.

3. The electrode of claim 1 wherein: said skin means is an aluminumsheet.

4. The electrode of claim 1 including: indicia means on the sheet memberoutlining a minimum external surface area of the skin means to ensure anelectrical contact of the electrode.

5. The electrode of claim 1 wherein: the minimum external surface areais at least square inches.

6. The electrode of claim 1 including: indicia means comprising lines onthe sheet member outlining at least one minimum external surface area.

7. A plate electrode comprising: a one-piece generally flat sheet memberhaving a flexible electrically nonconductive base, said base having asurface, a first skin of electrically conductive material located on afirst portion of said surface of the base, a second skin of electricallyconductive material spaced from the first skin located on a secondportion of said surface of the base, said first skin and second skinhaving electrically conductive external surface areas for engagementwith the surface of a body to make surface electrical con tacts betweenboth skins and the body, and means securing the inner sides of the firstskin and second skin to said one surface of the base.

8. The electrode of claim 7 wherein: the first skin and second skin havesubstantially the same external surface areas.

9. The electrode of claim 8 wherein: the first skin and second skin arelongitudinally separated along the central portion of the base.

10. The electrode of claim 7 wherein: said electrode has at least oneround corner.

11. The electrode of claim 7 wherein: the first skin and second skineach have edge portions that are turned adjacent the edges of the base.

12. The electrode of claim 7 wherein: said sheet member has a transversescored end adapted to be folded back.

13. The electrode of claim 7 wherein: the means securing the skins tothe surface comprise material impregnated into the base to bond thefirst skin and second skin to the base.

14. A plate electrode comprising: a one-piece generally flat sheetmember having a flexible electrically non-conductive base, said basebeing a flat flexible cardboard, a first skin of electrically conductivematerial secured to a first portion of one side of the base and a secondskin of electrically conductive material spaced from the first skinsecured to a second portion of said one side of the base, said firstskin and second skin comprising separate sheets of aluminumlongitudinally separated along the midsection of the base, andliquid-proof material impregnated throughout the cardboard base to bondthe aluminum to the base.

15. The electrode of claim 14 wherein: said sheet member has a pair ofround corners and said first and second skins each have edge portionsthat are turned adjacent the edges of the cardboard base.

16. The electrode of claim 7-wherein: said sheet member has at least onehole adjacent one edge thereof.

17. An electrode comprising: a flexible sheet member having a flatflexible base of electrically nonconductive cardboard, an electricallyconductive aluminum skin means secured to and substantially covering atleast one surface of the base, said skin means having a substantialsurface area for engagement with the surface of a body to make a largesurface electrical contact between the skin means and the body, andplastic material impregnated in the cardboard bonding the entire innerside of the skin means to said base.

18. The electrode of claim 17 wherein: said skin means comprise aplurality of separated skins attached to the base.

19. A plate electrode comprising: a one-piece generally flat sheetmember having an electrically nonconductive base, said base having asurface, a plurality of separated skin means of electrically conductivematerial located on separate portions of said surface of the base, saidskin means having electrically conductive external surface areas forengagement with the surface of a body to make surface electricalcontacts between said skin means and the body, and means securing theentire inside surfaces of the skin means to the surface of the base.

20. The electrode of claim 19 wherein: said plurality of skin meanscomprise a first skin and a second skin longitudinally separated alongthe center portion of the base.

21. The electrode of claim 19 wherein: the base has corners and theplurality of skin means comprises an electrically conductive skin ateach corner of the base.

22. The electrode of claim 19 wherein: said plurality of skin meanscomprises a first longitudinal skin along one side of the base and apair of separated skins located along the opposite side of the base.

23. The electrode of claim 22 including: electrical conductor meansconnected to one of said pair of skins to provide an electricalconnection along an edge of the base common with the first skin and theother of said pair of skins.

24. An electrode comprising: a flexible sheet member having a baselayer, said base layer being a generally flat flexible cardboard sheet,an electrically conductive skin comprising an aluminum sheet coveringone side of the cardboard sheet, said skin having a substantialelectrically conductive external surface area for engagement with thesurface ofa body to make a large surface electrical contact between theskin and the body, bond liquid-proof material impregnated throughout thecardboard sheet to bone the aluminum sheet to said cardboard sheet.

25. The electrode of claim 1 wherein: said sheet member has at least apair of rounded corners.

26. The electrode of claim 1 wherein: said sheet member has at least onehole adjacent one edge thereof.

27. The electrode of claim 1 wherein: said sheet member has a transversescored fold line along one edge of the flange.

28. The electrode of claim 17 wherein: said sheet member has at least apair of round corners.

29. The electrode of claim 17 wherein: said sheet member has at leastone hole adjacent one edge thereof.

30. The electrode of claim 17 wherein: at least one end of the sheetmember has a transverse scored end adapted to be folded back toward thebase.

31. An electrode releasably attachable to an electrical connector havingelectrical conductor means and projection means comprising: a one-piece,generally flat and flexible sheet member, said sheet member having anelectrically non-conductive base, said base being generally flat andhaving a surface on one side thereof, and electrically conductive skinmeans of a size to cover the surface of the base and adapted to beengaged by the conductor means when the connector is attached to thesheet member, said skin means having separate sections and a substantialsurface area for engagement with the surface of a body to make largesurface electrical contact between the skin means and the body, andmeans to secure the entire inside face of the skin means to said surfacethereby covering said surface, at least one hole in said sheet memberadjacent one edge thereof and between the separate sections of the skinmeans defining a stop edge engageable with said projection means toprevent accidental separation of the connector from the sheet member.

32. The electrode of claim 31 wherein: the hole is located adjacent oneend of the sheet member.

33. The electrode of claim 31 wherein: the sheet member has at least oneround corner.

34. The electrode of claim 31 wherein: the skin means has edge portionsthat are turned adjacent the edges of the base.

35. A plate electrode for engaging the surface of a body and releasablyattachable to an electrical connector having electrical conductor meansand leg means on itself forming a flange with a stop edge, said stopedge adapted to be engageable with said leg means to prevent accidentalseparation of the connector from the sheet member.

36. The electrode of claim 19 wherein: the plurality of skin meanscomprise three separate electrically conductive skins.

37. The electrode of claim 36 wherein: at least two of said skins havesubstantially the same external surface area.

1. An electrode for engaging the surface of a body and releasablyattachable to an electrical connector having electrical conductor meanscomprising: a one-piece flexible electrically non-conductive sheetmember having a generally flat base layer of flexible material, saidbase layer having a surface on at least one side thereof, electricallyconductive flexible skin means substantially covering at least onesurface of the base layer, said skin means having a substantialelectrically conductive external surface area for engagement with thesurface of a body to make a large surface electrical contact between theskin means and the body, and means securing the entire inner side ofsaid skin means to said one surface of the base layer, one edge of saidsheet member having a flange terminating in an edge.
 1. An electrode forengaging the surface of a body and releasably attachable to anelectrical connector having electrical conductor means comprising: aone-piece flexible electrically non-conductive sheet member having agenerally flat base layer of flexible material, said base layer having asurface on at least one side thereof, electrically conductive flexibleskin means substantially covering at least one surface of the baselayer, said skin means having a substantial electrically conductiveexternal surface area for engagement with the surface of a body to makea large surface electrical contact between the skin means and the body,and means securing the entire inner side of said skin means to said onesurface of the base layer, one edge of said sheet member having a flangeterminating in an edge.
 2. The electrode of claim 1 wherein: said flangeis secured to the base layer.
 3. The electrode of claim 1 wherein: saidskin means is an aluminum sheet.
 4. The electrode of claim 1 including:indicia means on the sheet member outlining a minimum external surfacearea of the skin means to ensure an electrical contact of the electrode.5. The electrode of claim 1 wherein: the minimum external surface areais at least 50 square inches.
 6. The electrode of claim 1 including:indicia means comprising lines on the sheet member outlining at leastone minimum external surface area.
 7. A plate electrode comprising: aone-piece generally flat sheet member having a flexible electricallynon-conductive base, said base having a surface, a first skin ofelectrically conductive material located on a first portion of saidsurface of the base, a second skin of electrically conductive materialspaced from the first skin located on a second portion of said surfaceof the base, said first skin and second skin having electricallyconductive external surface areas for engagement with the surface of abody to make surface electrical contacts between both skins and thebody, and means securing the inner sides of the first skin and secondskin to said one surface of the base.
 8. The electrode of claim 7wherein: the first skin and second skin have substantially the sameexternal surface areas.
 9. The electrode of claim 8 wherein: the firstskin and second skin are longitudinally separated along the centralportion of the base.
 10. The electrode of claim 7 wherein: saidelectrode has at least one round corner.
 11. The electrode of claim 7wherein: the first skin and second skin each have edge portions that areturned adjacent the edges of the base.
 12. The electrode of claim 7wherein: said sheet member has a transverse scored end adapted to befolded back.
 13. The electrode of claim 7 wherein: the means securingthe skins to the surfAce comprise material impregnated into the base tobond the first skin and second skin to the base.
 14. A plate electrodecomprising: a one-piece generally flat sheet member having a flexibleelectrically non-conductive base, said base being a flat flexiblecardboard, a first skin of electrically conductive material secured to afirst portion of one side of the base and a second skin of electricallyconductive material spaced from the first skin secured to a secondportion of said one side of the base, said first skin and second skincomprising separate sheets of aluminum longitudinally separated alongthe midsection of the base, and liquid-proof material impregnatedthroughout the cardboard base to bond the aluminum to the base.
 15. Theelectrode of claim 14 wherein: said sheet member has a pair of roundcorners and said first and second skins each have edge portions that areturned adjacent the edges of the cardboard base.
 16. The electrode ofclaim 7 wherein: said sheet member has at least one hole adjacent oneedge thereof.
 17. An electrode comprising: a flexible sheet memberhaving a flat flexible base of electrically non-conductive cardboard, anelectrically conductive aluminum skin means secured to and substantiallycovering at least one surface of the base, said skin means having asubstantial surface area for engagement with the surface of a body tomake a large surface electrical contact between the skin means and thebody, and plastic material impregnated in the cardboard bonding theentire inner side of the skin means to said base.
 18. The electrode ofclaim 17 wherein: said skin means comprise a plurality of separatedskins attached to the base.
 19. A plate electrode comprising: aone-piece generally flat sheet member having an electricallynon-conductive base, said base having a surface, a plurality ofseparated skin means of electrically conductive material located onseparate portions of said surface of the base, said skin means havingelectrically conductive external surface areas for engagement with thesurface of a body to make surface electrical contacts between said skinmeans and the body, and means securing the entire inside surfaces of theskin means to the surface of the base.
 20. The electrode of claim 19wherein: said plurality of skin means comprise a first skin and a secondskin longitudinally separated along the center portion of the base. 21.The electrode of claim 19 wherein: the base has corners and theplurality of skin means comprises an electrically conductive skin ateach corner of the base.
 22. The electrode of claim 19 wherein: saidplurality of skin means comprises a first longitudinal skin along oneside of the base and a pair of separated skins located along theopposite side of the base.
 23. The electrode of claim 22 including:electrical conductor means connected to one of said pair of skins toprovide an electrical connection along an edge of the base common withthe first skin and the other of said pair of skins.
 24. An electrodecomprising: a flexible sheet member having a base layer, said base layerbeing a generally flat flexible cardboard sheet, an electricallyconductive skin comprising an aluminum sheet covering one side of thecardboard sheet, said skin having a substantial electrically conductiveexternal surface area for engagement with the surface of a body to makea large surface electrical contact between the skin and the body, bondliquid-proof material impregnated throughout the cardboard sheet to bonethe aluminum sheet to said cardboard sheet.
 25. The electrode of claim 1wherein: said sheet member has at least a pair of rounded corners. 26.The electrode of claim 1 wherein: said sheet member has at least onehole adjacent one edge thereof.
 27. The electrode of claim 1 wherein:said sheet member has a transverse scored fold line along one edge ofthe flange.
 28. The electrode of claim 17 wherein: said sheet member hasat least a pair of round corners.
 29. The Electrode of claim 17 wherein:said sheet member has at least one hole adjacent one edge thereof. 30.The electrode of claim 17 wherein: at least one end of the sheet memberhas a transverse scored end adapted to be folded back toward the base.31. An electrode releasably attachable to an electrical connector havingelectrical conductor means and projection means comprising: a one-piece,generally flat and flexible sheet member, said sheet member having anelectrically non-conductive base, said base being generally flat andhaving a surface on one side thereof, and electrically conductive skinmeans of a size to cover the surface of the base and adapted to beengaged by the conductor means when the connector is attached to thesheet member, said skin means having separate sections and a substantialsurface area for engagement with the surface of a body to make largesurface electrical contact between the skin means and the body, andmeans to secure the entire inside face of the skin means to said surfacethereby covering said surface, at least one hole in said sheet memberadjacent one edge thereof and between the separate sections of the skinmeans defining a stop edge engageable with said projection means toprevent accidental separation of the connector from the sheet member.32. The electrode of claim 31 wherein: the hole is located adjacent oneend of the sheet member.
 33. The electrode of claim 31 wherein: thesheet member has at least one round corner.
 34. The electrode of claim31 wherein: the skin means has edge portions that are turned adjacentthe edges of the base.
 35. A plate electrode for engaging the surface ofa body and releasably attachable to an electrical connector havingelectrical conductor means and leg means comprising: a one-piece sheetmember having an electrically non-conductive base, an electricallyconductive skin means secured to one side of the base and engageablewith the electrical conductor means, said skin means having asubstantial surface area for engagement with the surface of a body tomake a large surface electrical contact between the skin means and thebody, one edge of said sheet member having a portion turned on itselfforming a flange with a stop edge, said stop edge adapted to beengageable with said leg means to prevent accidental separation of theconnector from the sheet member.
 36. The electrode of claim 19 wherein:the plurality of skin means comprise three separate electricallyconductive skins.